Lamp inspection apparatus



Oct. 10, 1961 n. L. SNYDER EI'AL 3,003,634

LAMP INSPECTION APPARATUS Filed Dec. 50, 1957 7 Sheets-Sheet 1 INVENTORSy 00mm L. s/vroz/r Oct. 10, 1961 D. L. SNYDER ETAL 3,003,634

LAMP INSPECTION APPARATUS Filed Dec. 30, 1957' 7 Sheets-Sheet 2 O 0,1961 D. SNYDER EI'AL 3,003,

LAMP INSPECTION APPARATUS Filed Dec. 30, 1957 7 Sheets-Sheet 3 BY 00mm1.. 51mm 1 C? I ATTOR/VD 1961 D. L. SNYDER ETAL 3,

LAMP INSPECTION APPARATUS Filed Dec. 30,1957 7 Sheets-Sheet 4 It o "3INVENTORS MAR/(l3 GISLEEEKG ROBERTA. HELW/G DONALD L. 177056 Oct. 10,1961 D. L. SNYDER EIAI. 3,003,634

LAMP INSPECTION APPARATUS Filed Dec. 30, 1957 7 Sheets-Sheet 5 MAE/USGISLEBEKG KOEK T A HELWIG ATIOR EY Oct. 10, 1961 Filed Dec. 30, 1957 L.SNYDER ETA].

LAMP INSPECTION APPARATUS 7 Sheets-Sheet 6 E Z 70 CdMPARATOR TEST l/N/7'0 [/0 VOL7' AJI- SOURCE 70 40 van ac. 0mg

INVENTORS Alli/[l3 GIJLEEMG' KORE/5'74 l/EUY/G DMALD L. .SWYDEK Oct. 10,1961 D. L. SNYDER ETAL 3,003,634

LAMP INSPECTION APPARATUS Filed Dec. 30, 1957 7 Sheets-Sheet 7 Flg'. l5

INVENTORS MARIUS GISLEBERG ROBERT A. HELWIG DONALD L. SNYDER ATTORNEUnited States Patent LAMP DJSPECTION APPARATUS Donald L. Snyder andMarius Gisleberg, Montoursville, and Robert A. Hal-wig, Williamsport,Pa., assignors, by mesne assignments, to Sylvania Electric ProductsInc.,

Wilmington, Del., a corporation of Delaware Filed Dec. 39, 1957, Ser.No. 705,930

4 Claims. (Cl. 209-1115) This invention relates to the manufacture ofelectric lamps and more particularly to the manufacture of photofiashlamps.

In the manufacture of photoflash lamps, an hermetically sealed,light-transmitting envelope is usually provided with a filling ofcombustible foil shredded to filamentary form, a combustion-supportinggas such as oxygen, and ignition means in operative relationship to thecombustible. The ignition means usually comprises a tungsten filamentsupported by a pair of lead-in wires provided with a quantity ofignition paste disposed thereon at or near the juncture thereof to thefilament. In the sequency of operations, a lamp envelope provided with afilling of a filamentary combustible is sealed to a lamp mount, the lampenvelope is evacuated, and the combustion-supporting gas such as oxygenis introduced at a precise, pre-determined pressure. If a photoflashlamp is to operate in the proper manner, it is necessary that theinitial oxygen fill pressure be maintained and that the lamp envelope betruly hermetically sealed. Even a slight leak in the lamp envelopedestroys the quality of the lamp because the contaminating air enteringthe lamp envelope tends to contribute to the possibility of the lampexploding and, in any case, the quantity and quality of the lightemitted when the lamp is fired is affected adversely.

In view of the foregoing, it has been the practice to test finishedlamps for the presence of air. One well known method for conducting sucha test is to excite the gases within the lamp with the aid of a standardhigh frequency coiler such as is customarily used in vacuum work. Ablue-green color of this discharge indicates a good lamp whereas apurple color indicates the presence of air. In this test the brightnessof the discharge is so low that it must be observed in total darkness.This testing method is time-consuming, expensive and not entirelyreliable.

Another testing method is shown and described in U.S. Patent 2,767,325which issued on October 16, 1956, to F. W. Harjes et al. In the methodof the referenced patent, small amounts of contaminating gases aredetected and measured accurately by permitting the light from theglowing flash lamp to fall on the cathode of a photomultiplier tubeprovided with a means for alternately scanning the total light output ofthe discharge and the light output less the ultra-violet rays, and abridge circuit associated therewith. The bridge circuit consists of twophoto tube load resistors and a galvanometer. The smaller currentcomponent, corresponding to the visible light output, is switched to afixed resistor, and the larger current component, corresponding to thetotal light of the gaseous discharge, is switched to a variableresistor. The variable resistor is adjusted until the galvanometerreaches zero current indicating that the average voltage drops acrossthe two resistors are equal, and hence the two resistors have the sameratio as the two components of current. The value of the variableresistance is therefore a measure of the degree of air contamination ofthe fiashlamp.

An object of this invention is to provide automatic apparatus fordetecting the presence of contaminants in gas filled envelopes.

Another object is to provide automatic apparatus for A further object isto provide automatic apparatus for detecting the presence ofcontaminants in gas filled envelopes and rejecting those devices foundto contain excessive contamination.

These and other objects are attained in accordance with the principlesof this invention by providing a conveyor of the endless chain type witha plurality of lampholders for carrying lamps through a pre-determinedpath, along which an inspection station and a rejection station aredisposed. A contamination detector, including a chamber for enclosing alamp therein, is disposed at the inspection station. Informationconcerning the condition of the lamp is obtained at the inspectionstation and transmitted to the rejection station where defecive lampsare: automatically removed from the line. I

A feature of the apparatus of this invention is the multi-unitcontamination detector which, in the specific embodiment described belowand illustrated in the accompanying drawings, tests five lamps at a timefor the presence of contaminants.

Another feature of the apparatus is the dual produc-E tion arrangementin which an upper conveyor and a lower conveyor operating in synchronismare each provided with an inspection station and a rejection stationassoci ated therewith, thus in effect, doubling the work load capacityof the apparatus.

In the specific embodiment of the apparatus shown in the accompanyingdrawings, FIGURE 1 is an end view partly in section of the apparatuslocated at the inspection station, the lamp-carrying conveyors beingomitted for clarity of illustration.

FIGURE 2 is a plan view of the apparatus located at the inspectionstation with a substantial portion of a cover removed to show more ofthe apparatus.

FIGURE 3 is an end view, partly in section and on an enlarged scale, ofthe apparatus at the inspection station, showing the inspection unitassociated with the lower conveyor.

FIGURE 4 is a plan view of the apparatus located at a rejection station.

FIGURE 5 is a front elevational view of the apparatus located at therejection station.

FIGURE 6 is a schematic diagram of an electrical circuit associated witheach inspecting device and rejecting device at the inspection stationand the rejection station respectively.

FIGURE 7 is a tinting chart illustrating the sequence of operations ofthe cam operated timing switches in terms of an indexing cycle of theapparatus.

FIGURE 8 is an elevational view of a lamp supporting jaw assembly takenalong the line 8-8 of FIGURE 3.-

Referring now to the drawings, and more particularly to FIGURES 3, 4, 5and 8 thereof, it will be noted that each lamp 113 is carried by a pairof jaws l2 and 14 pivotally mounted on rods 16 and 18 respectively onbracket 20 which is attached to mounting plate 22 on chain 24. The pivotrods 16 and 18 are each provided with a gear 26, the pair of gears 26meshing with one another at all times. A pair of mounting pins 30 project from the inside face of jaws 12 and 14 and support a spring 32extending therebetween. An apertured guide 34 is attached to one of thepins 39, the other pin 30' extending therethrough. A pair of camfollowers 36 and 38, the function of which will be describedhereinafter,- are mounted on the top of jaw 12. I T

It will be noted that each lamp supporting jaw assembly is furthercharacterized by a pair of rollers 40 mounted on bracket 20 and a pairof rollers 42 which are part of the chain 24. The rollers 40 of the lampsupporting jaw as semblies ride in track 44 and the rollers 42 of thechain Patented Oct. 10, 1961 24 ride in track 46. The relative locationof tracks 44 and 46 with respect to one another is such that they steadythe lamp supporting jaw assemblies or heads and define a fixed paththrough which the chain 24 moves. The tracks 44 and 46 are mounted onsuitable support castings (not shown) which are mounted on and keyed toa main support shaft 51 It will be noted from an examination of FIGURESl and that in the specific embodiment of the invention disclosed in theaccompanying drawings, a dual production arrangement is provided wherebysimilar mechanisms operate simultaneously on lamps carried by an upperand a lower conveyor chain. Since these mechanisms and their actuatingdevices are substantially the same, only one of the arrangements will bedescribed in detail.

Indexing means, not shown, advances five lamps at a time on each chainconveyor into the contamination check position shown in FIGURES 1, 2 and3 of the drawings, where five separate testing assemblies are located.Referring now particularly to FIGURES 1 and 2, a pair of standards 52,fixedly mounted on support shaft 50, have a support plate 54 attachedthereto and extending laterally therefrom to which a support bracket 56is attached by screws 57 (FIG. 2). A motor 58, connected to a source ofelectrical energy by cable 59, is mounted on the shelf portion ofsupport bracket 56, and is provided with a. shaft 60, on the outer endof which a sprocket 62 is disposed. A cover 64, attached to coversupport 66 by screws 68, encloses the motor 58 and thus protects it fromforeign matter, such as dust, etc. A bank of five light chopper housings70, is attached to the depending portion of support bracket 56, and aphotomultiplier unit 72 is in turn attached to each of the light chopperhousings 70 (FIG. 1).. The depending portion of support bracket 56 isprovided with five apertures within each of which a bearing housing 74is fitted, three of these being shown in FIGURE 2, the other two beinghidden by the support plate 54. Each bearing housing 74 is provided withbearings on which a shaft 76 (FIG. 3), which supports a sprocket 78,rotates. As shown in FIGURE 3, a pair of ultraviolet-absorbing filters65 are set in a filter support 67 mounted on the inner end of each ofthe shafts 76. A photomultiplier tube 69, such as a Type 931 forexample, is mounted in a suitable socket therefor in the photomultiplierunit 72 and extends into the light chopper housing 7 0 between the pairof filter elements 65. A glass plate 71 in the form of a window isdisposed in the bottom of the light chopper housing 70. A chain 79meshes with the several sprockets 73, the sprocket 62 and guidesprockets 77, thereby providing means for driving the several shafts 76associated with the several sprockets 78 from the motor 53 through shaft69 and sprocket 62. Each of the photomultiplier units 72 is connected toa 1200 volt input supply at terminal 81 The output from eachphotomultiplier tube is connected through a pair of terminals 82 to acomparator unit described below.

A base member 85 having a bank of live lamp inspection chambers soformed therein is mounted on an end of a support arm 86. A similar basemember 85a having a similar number of inspection chambers 84a formedtherein is mounted on an end of support arm 88. The top faces of thebase members 35 and 85a are fitted with a plurality of strips 87 ofresilient material such as rubber which extend about the periphery ofthe several inspection chambers. The support arms 36 and 88 are fixedlymounted on the upper'and lower ends respectively of a pair of supportrods 96 which are reciprocable in bushings in support casting 92. Thesupport casting 92 is provided with a pair of chambers 94, one of whichis shown in section in FIGURE 1. A pair of spring posts 96, mounted onsupport arm 88, are provided with a pair of springs 98, the springs andthe spring posts extending into the chambers 4 to insure a steady,smooth reciprocation of the support rods fit during operation. Thecasting 92 is attached to and supported by support shafts 50 and 101 Acam follower bracket 102, adjustably mounted on support arm 86 by meansof screw 104, has a cam follower 1&6 (FIGS. 2 and 3) attached thereto,the cam follower 156 riding on cam 10% on cam shaft 116/. This featureof adjustability is provided to permit slight adjustments in thedisposition of the cam follower 166 for reasons which will be pointedout hereinafter. Thus the cam 108 through cam follower 1G6, and springs98 effect reciprocation of support rods 90 within casting 92 andreciprocation of support arms 86 and 88 to move the bank of lampinspection chambers 84 and the bank of lamp inspection chambers 84a intoand out of encompassing relationship 7 with respect to lamps 16.

material mounted in the bottom of the base member 82a, a pair ofelectrical contact sleeves 114 extending through and supported bybushings 116 fitted in apertures therefor in block 112, and a pair ofsponge electrical contacts 118 fitted into and projecting from the pairof elec-' trical contact sleeves 114, only one of the sleeves 114 andcontacts 118 being shown in this figure. When the several lampinspection chambers 84 and Sea are in their rest position, the lower endof each of the sponge electrical contacts 118 are disposed in water intanks .119. As

shown in FIGURE 1, the tank 119 associated with the several inspectionchambers 84 is attached to the stationary support plate 54. The tank 119associated with the several inspection chambers 84a as shown in FIGURES1 and 3 isattached to a suitable stationary support not shown. Due tocapillary action, the water in the tanks 119 serves as a means forkeeping the sponge electrical contacts 118 moist. Each of the sleeves114 is spring loaded by a conical spring 120 to insure positive, yetflexible, engagement of the lamp 113* by the sponge contact 118 whenitis moved into operative relationship with respect thereto. One end of anelectrical conductor strip 122 is connected to a flange of bushing 116by screw 124, the other end thereof being secured to the threadeddepending portion of an electrical contact holder 126 mounted on aninsulator block 128 which is in turn attached to the base member 85a. Aspring loaded electrical contact arm 130, pivotally mounted on holder126, carries an electrical contact roller 132 in frictional engagementwith an electrical contact bar 134. As may be noted from an examinationof the upper testing unit in FIGURE 1, the electrical contact bar 134 isattached to a contact bar support 136 of insulating material, and thescrew 138 defines an electrical terminal for. connecting a source ofhigh frequency electrical energy to the contact bar 134 through cables135. A cover 140 is attached to the support 136 by screw 142.

After the contamination check has been effected on the two groups offive lamps each by the mechanisms shown in FIGURES 1, 2 and 3, the upperand lower conveyor chains 24 are indexed to bring the lamps into thereject station shown in FIGURES 4 and 5 Information concerning thecondition of the lamps, as detected at the inspection station, isreceived and stored in the circuit illustrated in FIGURE 6 and describedbelow, until the tested lamps reach the reject station. This informationis then transmitted to solenoids 152 disposed in housing 154 mounted onbrackets 156 attached to the main support shaft 50, the electricalconnections from the referenced circuit to the solenoids 152 being madethrough cable 158. A shrinkage bin 160, provided with five pockets inalignment with the five lamps It) at the gzject station, is also mountedon the main support shaft If a lamp 10 is detected as being defective,its corresponding solenoid 152 is energized when that lamp is at thereject station shown in FIGURES 4 and 5 and the solenoid plunger 162 isactuated. The actuated plunger 162 moves downwardly, striking camfollower 36 on jaw 12, thereby causing clockwise rotation of jaw 12about its pivot rod 16. Since, as was described above, gear 26 on rod 16meshes with a corresponding gear on rod 18, the clockwise rotation ofjaw 12 about its pivot rod 16 causes counter-clockwise rotation of jaw14 about its pivot rod 18, thus efiecting an opening of the jaws 12 and14 to release the lamp which falls into its pocket in shrinkage bin 160.When the solenoid 152 is decnergized, the plunger spring 164 returns theplunger from engagement with cam follower'36, thus permitting the spring32 which bridges the jaws 12 and 14 to effect a return thereof to theclosed position. Further indexing of the conveyor chains 24 advances thegood lamps 10 to an unloading station where suitable means not showndeflects the several cam followers 38 to effect an opening of theseveral jaws 12, 14 and discharge of the lamps to a suitable receptacle.

In the operation of the apparatus described above, photoflash lamps 10are advanced five at a time by both the upper and the lower conveyorchains 24 into the inspection station of FIGURES l, 2 and 3. With thelamps so disposed, the upper support arm 86 and the lower support arm 88move the base members 85 and 85a respectively upwardly to bring theseveral lamp inspection chambers 84 and 84a respectively intoencompassing relationship with respect to the lamps. Upward movement ofthe arm 86 is effected by the cam 108 through cam follower 106 and camfollower bracket 102. The cam 108 also effects the upward movement ofthe arm 88 through cam follower 106, cam follower bracket 102, arm 86,and support rods 90. The cam follower 106 is adjusted by means of screw104 to make sure that, at the end of the upward stroke of arms 86 and88, the strips 87 of resilient material which extend about the peripheryof the several inspection chambers 84 and 84a seal the chambers fromexternal light and provide the requisite darkened condition for lampinspection.

With the lamps 10 enclosed in the several darkened chambers 84 and 84a,and the moistened sponge electrical contacts 118 in engagement with thelamp envelopes, the contacts 118 are energized through cables 135 toeffect excitation of the gases in the lamps. The resultant glow in eachof the lamps 10 is picked up by the photomultiplier tube 69 (FIG. 3)through the glass plate 71. Since the support 67, to which the pair ofultraviolet-absorbing filters 65 are attached is being rotated by themotor 58, the chopped light received by the photomultiplier tube isalternately the total light output of the lamp and the visible light,the ultraviolet light being absorbed by the filters. The resultant waveform is fed to suitable diiferentiating circuitry in a comparator unit,not shown, which measures the difierences in light output of the glowdischarge in the photoflash lamp. Since variations in these differencesin light output are a function of contamination in the lamp, the outputof the comparator unit may be fed to a thyratron tube which is adjustedto fire only when the contamination exceeds a pre-determined amount. Thethyratron tube is connected to line 1 of the circuit of FIGURE 6.

The circuit of FIGURE 6 is one of ten identical circuits wired inparallel to receive, store and transmit information concerning thecondition of inspected lamps to the reject station shown in FIGURES 4and 5. Line 1 is connected to the comparator test unit, not shown. Line3 is connected to a 110 volt A.C. source. Line 7 is connected to a 40volt D.C. source. If a lamp has been detected as having more than apre-determined amount of contamination, a signal through line 1 from theaforementioned thyratron energizes coil relay 9 and closes its contacts9a and its contacts 9b in the holding circuit. Cam operated timingswitch 11 closes, energizing coil relay 13 and thus closing its coilcontacts 13a. The closing of coil contacts 13a permits 110 volt AC.power in line 3 to flow through coil contacts 13a and coil contacts 9a,thus the closed coil contacts 9a keep their coil relay 9 energized.

As the indexing starts, to move a set of lamps from the inspectionstation to the rejection station, cam oper-. ated timing switch 15closes and energizes coil relay 17. Energization of coil relay 17eifects a closing of its contacts 17a and thus permits volt AC. power inline 3 to flow through closed coil contacts 17a, and closed coilcontacts 912 to energize holding coil relay 19 and close coil contacts19a and 19b. Immediately after coil relay 19 is energized, cam operatedtiming switch 21 closes and energizes coil relay 23. Energization ofcoil relay 23 eifects a closing of its contacts 23a and thus permits 110volt A.C. power in line 3 to flow through closed coil contacts 23a andthe now closed coil contacts 19a to hold coil relay 19 energized. Closedcam operated timing switch 11 now opens, thus de-energizing coil relay13, opening coil contacts 13a, and dropping coil relay 9 out of thecircuit. Coil relay 19, which is being held energized by its owncontacts through closed coil contacts 23a, remains energized until thelamps reach the reject station.

When the lamps reach the reject station, cam operated timing switch 25closes, thus permitting energization of coil relay 27 and closing of itscontacts 27a. With 40 volt D.C. power from line 7 now flowing throughclosed coil contacts 27a and the previously closed coil contacts 192:,the solenoid 152 (corresponding to solenoid 152 in FIG. 5) is energizedand the defective lamp is rejected. If the lamp while in the testposition had been good, no electrical impulse would have been receivedby coil relay 9 and it would not have been energized. Consequently, whenthe good lamp reaches the rejection station, the lamp will not berejected.

A manually operated, normally open test switch 31 provides a means fortesting the circuit since the closingthereof simulates a defective lampcondition. Signal light 33 across solenoid 152 provides a visual meansof checking the circuitry therethrough. Signal lights 35, 37, 39 and 41provide a visual means for checking the oper ation of timing switches17, 13, 27 and 23, respectively.- In FIGURE 7 line A represents oneindexing cycle of the machine with dwell time extending from 0 to about240, actual indexing movement occurring from about 240 to 360. Line Brepresents switch 21 open from 60 to and closed during the remainder ofthe cycle. Line C represents switch 11 open from 270 to nearly 360 andclosed during the remainder of the cycle. Line D represents switch 15closed from 250 to 300 and open during the remainder of the cycle. LineE represents switch 25 closed from 60 to about 105 and open during theremainder of the cycle.

What we claim is:

1. in apparatus for detecting contaminants in a sealed,light-transmitting, gas-filled lamp, by a comparative analysis of thespectral distribution of light from a gaseous discharge within saidlamp, the combination of: a conveyor; lampholders, for supporting lamps,mounted on said conveyor; an inspection chamber disposed along the pathtraversed by said conveyor; a pair of electrodes mounted in saidchamber; means for advancing said chamber into encompassing relationshipwith respect to a lamp held by one of said lampholders on said conveyorand advancing said electrodes into engagement with said lamp envelope; aphototube in light-receiving relationship with respect to a lamp in saidchamber; means for energizing said electrodes whereby a glow dischargeis produced in said lamp envelopes; and means for alternately passingthe total light and the visible light of said glow discharge to saidphototube. V

2. In apparatus for detecting contaminants in a sealed,light-transmitting, gas-filled lamp, by a comparative analysis of thespectral distribution of light from a gaseous discharge within saidlamp, the combination of: a conveyor; lampholders, for supporting lamps,mounted on said conveyor; an inspection chamber disposed along the pathtraversed by said conveyor; a pair of electrodes mountedin said chamber;means for advancing said chamber into encompassing relationship withrespect to a lamp, held by one of said lampholders on said conveyor andadvancing said electrodes into engagement with said lamp envelope; aphototube in light-receiving relationship with respect to a lamp in saidchamber; means for energizing said electrodes whereby a glow dischargeis produced in said lamp envelope; means for alternately passing thetotal light and the visible light of said glow discharge to saidphototube; a reject st'a tion, disposed along the path traversed by saidconveyor, subsequent to said'inspection chamber; means at said rejectionstation for opening said lampholders; and means, responsive tovariations in the difierences between the total light and visible lightfrom said glow discharge received by said phototube, for identifying acontaminated lamp and actuating said lampholder' opening means to effectrelease of the contaminated lamp there from. r

'3. In apparatus for detecting contaminants in a sealed,light-transmitting, gas-filled lamp, by a comparative analysis of thespectral distribution of light from a gaseous discharge within saidlamp, the combination of: a conveyor; a plurality of lampholders, forsupporting lamps, mounted on said conveyor; a plurality of inspectionchambers disposed along the path traversed by said conveyor; a pair ofelectrodes mounted in each of said chambers; means for advancing saidchambers into encompassing relationship with respect to lamps held bysaid lampholders on said conveyor and advancing each of said pairs ofelectrodes into engagement with each of said lamp envelopes; a phototnbein light-receiving relationship with respect to each of said lamps insaid chambers; means for energizing said electrodes whereby a glowdischarge is produced in said lamp envelopes;

and means for alternately passing the total light and the 4. Inapparatus for detecting contaminants in a sealed, light-transmitting,gas-filled lamp, by a comparatively analysis of the spectraldistribution of light from a gaseous discharge within said lamp, thecombination of: a conveyor; a plurality of lampholders, for supportinglamps, mounted on said conveyor; a plurality of inspection chambersdisposed along the path traversed by said conveyor; a pair of electrodesmounted in each of said chambers; means for advancing said chambers intoencompassing relationship with respect to lamps held by said lampholderson said conveyor and advancing each of said pairs of electrodes intoengagement with each of said lamp envelopes; a phototube inlight-receiving relationship with respect to each of said lamps in saidchambers; means for energizing said electrodes whereby a glow dischargeis produced in said lamp envelopes; means for alternately passing thetotal light and the visi ble light of each of said glow discharges totheir re-z and visible light from each glow discharge received by itsrespective phototube, for identifying a contaminated lamp and actuatingits respective lampholder opening means to effect release of thecontaminated lamp therefrom.

References Cited in the file or this patent UNITED STATES PATENTS1,626,359 Rundell Apr. 26, 1927 2,183,606 Day Dec. 19, 1939 2,407,062Darrah Sept. 3, 1946 2,439,373 Stearns Apr. 6', 1948 2,580,275 7 BickleyDec. 25, 1951 2,734,628 Schlayer Feb. 14, 1956 2,767,325 Harjes et al.Oct. 16, 1956

